The dental handpiece of the invention may be of the type which includes a tubular main body with connecting means at one end of the body for hoses from a compressed air and pressurized water supply; and having conduits extending longitudinally through the body which are coupled to the hoses to supply a stream of water adjacent to the other end of the body, and also to supply compressed air to a high speed turbine mounted at the other end of the body.
The compressed air is directed into the turbine to impinge on the blades of a rotor contained within the turbine housing. The turbine rotor is mounted on bearings at each end of the housing, the bearings being lubricated by oil mist carried by the incoming compressed air.
An exhaust port is provided at one end of the housing, the exhaust port being coupled to an appropriate vacuum source through a hose. This expedient serves to increase the power output of the turbine which, in turn, permits the turbine to be operated at lower speeds than the prior art handpieces for a desired torque output with resulting decrease in the noise level of the instrument. This feature also permits smaller hoses to be used for supplying the compressed air to the turbine, as compared with the hoses used in the prior art handpieces to achieve an equivalent output torque.
Accordingly, the primary objective of the present invention is to provide an improved dental handpiece apparatus of increased efficiency as compared with the prior art apparatus, and which is capable of producing a desired torque at lower speeds and lower noise level than is possible with the prior art apparatus.